U.S. patent number 4,562,232 [Application Number 06/685,378] was granted by the patent office on 1985-12-31 for copolyetherester-dimer ester-block copolymers.
This patent grant is currently assigned to General Electric Company. Invention is credited to Gary F. Smith.
United States Patent |
4,562,232 |
Smith |
December 31, 1985 |
Copolyetherester-dimer ester-block copolymers
Abstract
Improved copolyether ester elastomers having excellent melt and
crystallization temperatures as well as improved compression set as
compared to prior art copolyetheresters are prepared by
incorporating therein dimer ester polymer blocks.
Inventors: |
Smith; Gary F. (Pittsfield,
MA) |
Assignee: |
General Electric Company
(Pittsfield, MA)
|
Family
ID: |
24751951 |
Appl.
No.: |
06/685,378 |
Filed: |
December 24, 1984 |
Current U.S.
Class: |
525/444.5;
528/295.3 |
Current CPC
Class: |
C08G
63/66 (20130101) |
Current International
Class: |
C08G
63/00 (20060101); C08G 63/66 (20060101); C08G
063/76 () |
Field of
Search: |
;525/444.5
;528/295.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Phynes; Lucille M.
Attorney, Agent or Firm: Welch, II; Edward K. Mufatti;
William F. Harbour; John W.
Claims
I claim:
1. A thermoplastic elastomeric block copolyether ester comprising
the reaction product of
(a) at least one C.sub.2 to C.sub.20 diol,
(b) at least one C.sub.6 to C.sub.20 aromatic dicarboxylic
acid,
(c) at least one poly(alkylene ether)glycol having a molecular
weight of from about 350 to about 12000 and
(d) a property improving amount of a dimer ester polymer sufficient
to improve compression set.
2. The composition of claim 1 wherein the diol is selected from
C.sub.2 to C.sub.20 aliphatic and cycloaliphatic diols and wherein
at least 60 mole percent of the diol is the same.
3. The composition of claim 1 wherein the diol is selected from the
group consisting of C.sub.2 to C.sub.8 aliphatic diols and wherein
at least 80 mole % of the diol is the same.
4. The composition of claim 3 wherein the diol is
1,4-butanediol.
5. The composition of claim 1 wherein the diol is 1,4-butane
diol.
6. The composition of claim 1 wherein the aromatic dicarboxylic
acid is a C.sub.6 dicarboxylic acid or the C.sub.8 ester derivative
thereof and at least 60 mole % of the acid is the same.
7. The composition of claim 1 wherein the aromatic dicarboxylic
acid is a C.sub.6 dicarboxylic acid or the C.sub.8 ester derivative
thereof and at least 80 mole % of the acid is the same.
8. The composition of claim 7 wherein the aromatic dicarboxylic
acid is dimethylterephthalate.
9. The composition of claim 1 wherein the aromatic dicarboxylic
acid is dimethylterephthalate.
10. The composition of claim 1 wherein reactants (a) and (b) are
prereacted to form a low molecular weight polyester prior to
polymerization of the composition.
11. The composition of claim 10 wherein the preformed low molecular
weight polyester is represented by repeating units of the formula:
##STR2## where D is a C.sub.2 to C.sub.8 organic radical remaining
after removal of the terminal hydroxy groups of an aliphatic or
cycloaliphatic diol.
12. The composition of claim 11 wherein the preformed low molecular
weight polyester is poly(butylene terephthalate).
13. The composition of claim 1 wherein the poly(alkylene
ether)glycol has a molecular weight of from about 900 to about
4000.
14. The composition of claim 13 wherein the poly(alkylene
ether)glycol is selected from the group consisting of
poly(propylene ether)glycol, poly(tetramethylene ether)glycol and
copoly(propylene ether-ethylene ether)glycol.
15. The composition of claim 13 wherein the poly(alkylene
ether)glycol is poly(tetramethylene ether)glycol.
16. The composition of claim 1 wherein the dimer ester polymer is
derived from a C.sub.2 to C.sub.20 aliphatic or cycloaliphatic diol
and a dimer acid.
17. The composition of claim 1 wherein the dimer ester polymer is
derived from a C.sub.2 to C.sub.6 aliphatic diol and dimer
acid.
18. The composition of claim 1 wherein the block copolymer
comprises from about 40 to about 90 parts by weight of polyester
units derived from (a) and (b), from about 5 to about 60 part by
weight of poly(alkylene ether) units derived from (c) and from
about 2 to about 30 parts by weight of dimer ester polymer units
derived from (d).
19. The composition of claim 1 wherein the block copolymer
comprises from about 60 to about 80 parts by weight of polyester
units derived from (a) and (b), from about 15 to about 40 parts by
weight of poly(alkylene ether) units derived from (c) and from
about 5 to about 15 parts by weight of dimer ester polymer units
derived from (d).
20. A thermoplastic elastomeric composition comprising the reaction
product of
(a) butanediol
(b) dimethylterephthalate
(c) poly(tetramethylene glycol) and
(d) a dimer ester polymer derived from a C.sub.2 to C.sub.20 diol
and dimer acid.
Description
The present invention relates to elastomeric thermoplastic block
copolymers derived from polyester blocks, poly(alkylene ether)
blocks and dimer ester blocks having greatly improved compression
set and melting and crystallization characteristics as compared to
random copolyetheresters having incorporated therein dimer
acid.
Copolyetherester elastomers are well known. Generally, they are
prepared by conventional esterification/condensation processes for
the preparation of polyesters from diols, dicarboxylic acids and
poly(alkylene ether) glycols of molecular weight of from 350-6000.
Such copolyetheresters and their methods of production are
described in, for example, U.S. Pat. Nos. 3,023,123; 3,763,109;
3,651,014; 3,766,146 and 3,663,653 and are available from a number
of sources commercially including E.I. duPont under the trademark
Hytrel.
It is likewise known to prepare segmented copolyester elastomers
from low molecular weight diols, dicarboxylic acid and dimer acid,
see e.g. Hoeschele, U.S. Pat. No. 3,954,689. Additionally, it is
known to make copolyetherester elastomers, such as described above,
wherein some of the dicarboxylic acid and/or poly(alkylene
ether)glycol is substituted by dimer acid. For example, Tung (U.S.
Pat. No. 4,254,001) describes random copolyesters derived from
terephthalic acid, dimer acid, butanediol and poly(tetramethylene
ether)glycol having good elastomeric characteristics which can be
used to make films, fibers and molded parts. Finally, McGirk (U.S.
Pat. No. 4,264,761) describes random copolyetheresters suitable as
barrier coats having incorporated therein dimer acid.
While the foregoing dimer modified copolyesters and
copolyetheresters have good elastomeric properties, their use may
be somewhat limited by their low crystallization and melt
temperatures and average compression set properties as compared to
unmodified copolyetheresters. Alternatively, while the unmodified
copolyetheresters have the good melt and crystallization
properties, certain elastomeric properties as well as stability
characteristics are not as good as with the dimer modified
compositions.
It is an object of the present invention to provide thermoplastic
elastomeric compositions having excellent crystallization and melt
temperatures and characteristics as well as superior compression
set as compared to either dimer modified and unmodified random
copolyetheresters.
SUMMARY OF THE INVENTION
The improved thermoplastic elastomeric block copolymers of the
present invention may be prepared by conventional
esterification/transesterification processes from (a) an aromatic
polyester, (b) a poly(alkylene ether)glycol having a molecular
weight of from about 350 to about 12000, and (c) a property
improving amount of a long chain aliphatic polyester based on dimer
acid. The aromatic polyester (a) may be prepared in a separate step
prior to polymerization or it can be prepared during the
polymerization. Similarly, any combination of the reactants (a),
(b) or (c) may be prereacted in a separate prepolymerization step
prior to final polymerization of the polymers of the present
invention.
In general, the block copolymers of the present invention comprise
from about 40 to about 90, preferably from about 60 to about 80,
parts by weight aromatic polyester blocks (a); from about 5 to
about 60, preferably from about 15 to about 40, parts by weight of
poly(alkylene ether)glycol blocks (b) and from about 2 to about 30,
preferably from about 5 to about 15 parts by weight of dimer ester
polymer or oligomer blocks. These compositions may contain and
preferably do contain stabilizers and the like.
DETAILED DESCRIPTION
The aromatic polyesters (a) are prepared by conventional
esterification processes from (i) one or more diols and (ii) one or
more aromatic dicarboxylic acids.
Diols which are suitable for use in preparing the aromatic
polyester blocks are saturated and/or unsaturated aliphatic,
cycloaliphatic, and aromatic dihydroxy compounds. They will
preferably have a molecular weight of about 300 or less. Preferred
are diols with 2-20 carbon atoms such as ethylene, propylene,
tetramethylene, pentamethylene, 2-methyl trimethylene,
2,2-dimethyltrimethylene, hexamethylene and decamethylene glycols;
dihydroxy cyclohexane; cyclohexane dimethanol; resorcinol;
hydroquinone; 1,5-dihydroxy naphthalene, 2-octyl undecanediol or
mixtures of any one or more of these diols with unsaturated diols
such as butene-diol, hexene-diol, etc. Especially preferred are
saturated aliphatic diols, mixtures thereof or a mixture of a
saturated diol(s) with an unsaturated diol(s), each diol containing
2-8 carbon atoms. Included among the aromatic dihydroxy compounds
which can be used are 4,4' dihydroxy diphenyl,
bis(p-hydroxyphenyl)methane, and 2,2-bis(p-hydroxyphenyl)propane.
Equivalent ester-forming derivatives of diols are also useful
(e.g., ethylene oxide or ethylene carbonate can be used in place of
ethylene glycol).
Where more than one diol is employed, it is preferred that at least
about 60 mole %, based on the total diol content, be the same diol,
most preferably at least 80 mole %. The preferred polyesters are
those in which 1,4- butanediol is present in a predominant amount,
most preferably when 1,4-butanediol is the only diol.
Dicarboxylic acids suitable for use in preparing the polyester
block are the C.sub.6 to .sub.20 aromatic dicarboxylic acids, the
esters thereof and the equivalent ester-forming derivatives
thereof, including for example the acid halides and anhydrides,
provided the number of carbons refers only to the acid itself.
As the term is used herein, aromatic dicarboxylic acids are
dicarboxylic acids having two carboxyl groups attached to a carbon
atom in an isolated or fused benzene ring system. It is not
necessary that both functional carboxyl groups be attached to the
same aromatic ring and where more than one ring is present, they
can be joined by aliphatic or aromatic divalent radicals or
divalent radicals such as --O-- or --SO.sub.2 --. Preferred
aromatic dicarboxylic acids include for example terephthalic acid,
isophthalic acid, phthalic acid, napthalene-2,6-dicarboxylic acid,
napthalene-1,5-dicarboxylic acid naphthalene-2,7-dicarboxylic acid,
oxybis(benzoic acid), 4,4-sulfonyl dibenzoic acid and halo and
C.sub.1 to C.sub.12 alkyl, alkoxy and aryl ring substitution
derivatives thereof.
Finally, where mixtures of dicarboxylic acids are employed in the
preparation of the aromatic polyesters, it is preferred that at
least about 60 mole %, preferably at least about 80 mole %, based
on 100 mole % of dicarboxylic acid, be of the same dicarboxylic
acid or ester derivative thereof. The preferred aromatic polyesters
are those in which dimethylterephthalate is the predominant
dicarboxylic acid, most preferably when dimethylterephthalate is
the only dicarboxylic acid.
Optionally, the aromatic polyesters may contain a minor amount,
generally less than 20 mole percent, preferably less than 10 mole
percent, based on the dicarboxylic acid(s), of a C.sub.4 to
C.sub.16 aliphatic and/or cycloaliphatic dicarboxylic acid.
Exemplary of the aliphatic and cycloaliphatic dicarboxylic acid
there may be given glutaric acid, adipic acid, azelaic acid,
succinic acid, 1,4-cyclohexane dicarboxylic acid, tetramethyl
succinic acid and cyclopentane dicarboxylic acid.
These aromatic polyesters (a) may be prepared in a separate step
prior to polymerization of the block copolymers of the present
invention or the reactants therefore may be directly added to the
reaction vessel with the poly(alkylene ether)glycol (b) and/or
dimer ester (c) and polymerized during the overall polymerization
process. If a prepolymer or preformed aromatic polyester is to be
used, they may be prepared by conventional processes as described
in, for example, U.S. Pat. Nos. 2,465,319; 3,047,539 and 2,910,466,
herein incorporated by reference. Preferred aromatic polyester
prepolymers will generally have an intrinsic viscosity of at least
about 0.2 dl/g, most preferably at least about 0.3 dl/g as measured
in a 60:40 phenol/tetrachlorethane mixture. Of course, lower
intrinsic viscosity polyesters will also be suitable.
Preferred aromatic polyesters are of the formula: ##STR1## where D
is a C.sub.2 to C.sub.8 organic radical remaining after removal of
the terminal hydroxy groups of an aliphatic or cycloaliphatic diol.
Especially preferred aromatic polyesters are poly(butylene
terephthalate), poly(butylene terephthalate-co-isophthalate) and
poly(ethylene terephthalate), most preferably poly(butylene
terephthalate).
Poly(alkylene ether)glycols (b) suitable for use in the prepartion
of the block copolymer of the present invention will generally have
a molecular weight of from about 350 to about 12000, preferably
from about 900 to about 4000. Additionally, they will generally
have a carbon-to-oxygen ratio of from about 1.8 to about 4.3.
Representative of the long chain poly(alkylene ether)glycols that
may be used, there may be given poly(ethylene ether)glycol;
poly(propylene ether)glycol; poly(tetramethylene ether)glycol;
random or block copolymers of ethylene oxide and propylene oxide,
including propylene oxide terminated poly(ethylene ether)glycol;
and random or block copolymers of tetrahydrofuran with minor
amounts of a second monomer such as ethylene oxide, propylene oxide
and methyl tetrahydrofuran. Polyformal glycols prepared by reacting
formaldehyde with diols such as 1,4-butanediol and 1,5-pentanediol
are also useful. Especially preferred poly(alkylene ether)glycols
are poly(propylene ether)glycol, poly(tetramethylene ether)glycol
and poly(ethylene ether)glycols end capped with poly(propylene
ether)glycol and/or propylene oxide.
While copolyetheresters prepared from the foregoing components have
good melting and crystallization characteristics, their elastomeric
properties are only fair. Modification thereof by substituting
dimer acid for some of the dicarboxylic acid and/or poly(alkylene
ester) results in random copolyetheresters having good elastomeric
properties but poorer melt and crystallization temperatures and
characteristics. Applicant has now surprisingly found that a dimer
ester oligomer or polymer when incorporated as a block segment in a
ternary block-copolymer manifests unexpectedly improved melt and
crystallization temperatures and characteristics as well as
unexpectedly and markedly improved compression set. In general,
these compositions have excellent molding characteristics and
stress-strain elastomeric properties.
The dimer ester oligomers and polymers suitable for providing the
unexpectedly improved properties of the present invention are the
esterification/polycondensation reaction product of one or more
diols and dimer acid. Diols suitable for the preparation of the
dimer ester oligomer or polymer block are as described above for
the preparation of the aromatic polyester (a). Preferred diols are
the aliphatic diols including for example ethylene glycol;
1,4-butanediol; 1,6-hexanediol; neopentyl glycol and
2-octyl-undecanediol.
Dimer acids useful in the preparation of the dimer ester oligomer
and/or polymer block are prepared by the dimerization of
unsaturated fatty acids of 18 carbons. Exemplary of fatty acids
from which they are prepared there may be given oleic acid,
linoleic acid and linolenic acid. The preparation and structure of
dimer acid is described in Journal of the American Oil Chemists
Society, 39, 534-545 (1962), Journal of the American Chemical
Society 66, 84 (1944) and U.S. Pat. No. 2,347,562, all incorporated
herein by reference. Suitable dimer acids may be employed in their
unhydrogenated or hydrogenated form and include the acid
functioning derivatives thereof.
Several grades of dimer acid are available commercially which vary
in monomer and trimer content. Inclusive of suitable commercial
dimer acids there may be given those available from Emery
Industries under the tradenames EMPOL 1010 (a hydrogenated dimer
acid) and EMPOL 1014. EMPOL 1010 is reported as typically
containing 97% dimer acid, 3% trimer acid and essentially no
monobasic acid and extremely low unsaturation, whereas EMPOL 1014
is typified as containing 95%, 4% and 1% of dimer, trimer and
monobasic acids respectively. Also available are the dimer acids
sold under the tradename HYSTRENE from the Humko Products Division
of Witco Chemical Corporation, especially HYSTRENE 3695 which
typically contains 95% dimer acid and a weight ratio of dimer to
trimer of 36:1. Preferred grades are substantially free of such
monomer and trimer fractions, most preferably less than 5% by
weight, and are fully saturated, or substantially so. Where
desirable, the dimer acid member may be substantially freed of
monomer and trimer fractions by molecular distillation or other
suitable means. Finally, an additional source of suitable dimer
acids is the Henkel Corporation. As with the foregoing sources,
Henkel dimer acids are available in unhydrogenated and hydrogenated
versions. Preferred dimer acids for the purpose of the present
invention are the hydrogenated C.sub.36 dimer acids.
The dimer ester prepolymers are prepared by conventional
esterification processes as mentioned above for the aromatic
polyesters (a). In general, it is preferred that the degree of
polymerization of the dimer ester oligomer or polymer be such as to
provide a prepolymer having a Brookfield viscosity of at least
about 10,000 centipoise, preferably at least about 20,000
centipoise, as measured at 60.degree. C. with a No. 6 spindle. Of
course it is anticipated that lower viscosity polyesters will be
useful herein and are thus intended within the full scope of the
present invention. For example, applicant believes the invention is
applicable to dimer ester oligomers of MW of at least about 1200,
preferably at least about 1500.
The block copolymers of the present invention will generally
comprise from about 40 to about 90 percent by weight of the
aromatic polyester blocks (a), from about 5 to about 60 percent by
weight of long chain poly(alkylene ether) blocks (b) and from about
2 to about 30 percent by weight of dimer ester oligomer or polymer
blocks (c). Preferred compositions will comprise from about 60 to
about 80 percent by weight of (a), from about 15 to about 40
percent by weight of (b) and from about 5 to about 15 percent by
weight of (c).
The block copolymers described herein may be made conveniently by
conventional ester interchange reactions. Exemplary of the
processes that may be used are as set forth in, for example, U.S.
Pat. Nos. 3,023,192; 3,763,109; 3,663,653 and 3,801,547, herein
incorporated by reference, as well as those already referred to
above. Typically, the aromatic polyester (a), long chain
poly(alkylene ether)glycol (b) and the dimer ester oligomer and/or
polymer (c) is heated to about 150.degree. C. to 260.degree. C. at
about atmospheric pressure while distilling off volatiles.
Depending upon temperature, catalyst, excess diol and degree of
hydroxy end capping of the aromatic polyester (a), this stage of
polymerization is complete within a few minutes to a few hours.
This procedure results in the preparation of a low intrinsic
viscosity copolymer which can be carried to a high molecular weight
(high intrinsic viscosity, e.g. greater than about 0.6, preferably
greater than about 0.8) copolyester by polycondensation. During
polycondensation, excess diol in the system as well as diol end
caps on the low molecular weight prepolymer are distilled off.
Additional ester interchange occurs during this distillation to
increase the molecular weight of the polymer and to randomize the
arrangement of the individual block units. During polycondensation,
the temperatures of the reaction system is elevated to between
about 240.degree. C. and 300.degree. C. and the pressure decreased
to less than about 670 Pa, more preferably less than about 250
Pa.
Alternatively, as mentioned above, the reactants for the aromatic
polyester (a) may be charged to the system along with the long
chain poly(alkylene ether)glycol (b) and dimer ester oligomer
and/or polymer (c). In this instance, the long chain poly(alkylene
ether)glycol and dimer ester oligomer or polymer together with the
dicarboxylic acid(s) or methylester(s) thereof and a molar excess,
as compared to the acid, of the diol(s) are changed into the
reaction vessel and heated at 150.degree. to 260.degree. C. Heating
is continued until methanol and/or water evolution is substantially
complete. Again depending upon temperature, catalyst and diol
excess, this polymerization is complete within a few minutes to a
few hours. The prepolymer as produced is then carried to a high
molecular weight copolymer by polycondensation as described
above.
While not required, it is customary and preferred to utilize a
catalyst or catalyst system in the process for the production of
the block copolyesters of the present invention, as well as for the
preparation of the aromatic polyester (a) and dimer ester oligomer
and/or polymer (c) preformed blocks. In general, any of the known
ester-interchange and polycondensation catalysts may be used.
Although two separate catalysts or catalyst systems may be used,
one for ester interchange and one for polycondensation, it is
preferred, where appropriate, to use one catalyst or catalyst
system for both. In those instances where two separate catalysts
are used, it is preferred and advantageous to render the
ester-interchange catalyst ineffective following the completion of
the precondensation reaction by means of known catalyst inhibitors
or quenchers, in particular, phosphorus compounds such as
phosphoric acid, phosphenic acid, phosphonic acid and the alkyl or
aryl esters or salts thereof, in order to increase the thermal
stability of the resultant polymer.
Exemplary of the suitable known catalysts there may be given the
acetates, carboxylates, hydroxides, oxides, alcoholates or organic
complex compounds of zinc, manganese, antimony, cobalt, lead,
calcium and the alkali metals insofar as these compounds are
soluble in the reaction mixture. Specific examples include, zinc
acetate, calcium acetate and combinations thereof with antimony
tri-oxide and the like. These catalysts as well as additional
useful catalysts are described in U.S. Pat. Nos. 2,465,319;
2,534,028; 2,850,483; 2,892,815; 2,937,160; 2,998,412; 3,047,539;
3,110,693 and 3,385,830, among others, incorporated herein by
reference.
Where the reactants and reactions allow, it is preferred to use the
titanium catalysts including the inorganic and organic titanium
containing catalysts, such as those described in, for example, U.S.
Pat. No. 2,720,502; 2,727,881; 2 729,619; 2,822 348; 2,906,737;
3,047,515; 3,056,817; 3,056,818; and 3,075,952 among others,
incorporated herein by reference. Especially preferred are the
organic titanates such as tetra-butyl titanate, tetra-isopropyl
titanate and tetra-octyl titanate and the complex titanates derived
from alkali or alkaline earth metal alkoxides and titanate esters,
most preferably the organic titanates. These too may be used alone
or in combination with other catalysts such as for example, zinc
acetate, calcium acetate, manganese acetate or antimony trioxide,
and/or with a catalyst quencher as described above. The catalyst
should be used in amounts of from about 0.005 to about 2.0 percent
by weight based on the total reactants.
Both batch and continuous methods can be used for any stage of the
block copolyester polymer preparation. Polycondensation of
prepolymer can also be accomplished in the solid phase by heating
finely divided solid prepolymer in a vacuum or in a stream of inert
gas to remove liberated low molecular weight diol. This method has
the advantage of reducing degradation because it must be used at
temperatures below the softening point of the prepolymer. The major
disadvantage is the long time required to reach a given degree of
polymerization.
Although the copolyesters of this invention possess good resistance
toward heat aging and photodegradation, it is advisable to
stabilize these compositions by incorporating antioxidants in the
copolyester compositions.
Most any oxidative and/or thermal stabilizer known in the art for
copolyetheresters may be used in the practice of the present
invention. These can be incorporated into the compositions either
during polymerization or while in a hot melt stage following
polymerization. Satisfactory stabilizers include the phenols and
their derivatives, amines and their derivatives, compounds
containing both hydroxyl and amine groups, hydroxyazines, oximes,
polymeric phenolic esters and salts of multivalent metals in which
the metal is in its lower valence state.
Representative phenol derivatives useful as stabilizers include
3,5-di-tert-butyl-4-hydroxy hydrocinnamic triester with
1,3,5-tris-(2-hydroxyethyl)-s-triazine-2,4,6-(1H,3H,5H)trione
(Goodrite 3125);
N,N'-hexamethylene-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide);
4,4'- bis(2,6-ditertiary-butylphenol);
1,3,5-trimethyl-2,4,6-tris(3,5-ditertiarybutyl-4-hydroxybenzyl)benzene
and 4,4'-butylidenebis(6-tertiary-butyl-m-cresol). Various
inorganic metal salts or hydroxides can be used as well as organic
complexes such as nickel dibutyl dithiocarbonate, manganous
salicylate and copper 3-phenyl-salicylate. Typical amine
stabilizers include 4,4-bis(.alpha.,.alpha.-dimethylbenzyl)
diphenylamine, N,N'-bis(betanaphthyl)-p-phenylene diamine;
N,N'-bis(1-methylheptyl) -p-phenylene diamine and either
phenyl-beta-naphthyl amine or its reaction products with aldehydes.
Mixtures of hindered phenols with esters of thiodipropionic acid,
mercaptides and phosphite esters are particularly useful.
Additional stabilization to ultraviolet light can be obtained by
compounding with various UV absorbers such as substituted
benzophenones and/or benzotriazoles.
Further, the properties of these polyesters can be modified by
incorporation of various conventional inorganic fillers such as
carbon black, silica gel, alumina, clays and chopped fiberglass.
These may be incorporated in amounts up to 50% by weight,
preferably up to about 30% by weight. In general, these additives
have the effect of increasing the modulus of the material at
various elongations.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following examples are presented as illustrative of the present
invention and are not to be construed as limiting thereof.
Compression set properties were determined in accordance with
ASTM395B at 25.degree. C. and 70.degree. C. for a period of 22
hours.
Examples 1-13, Comparative Examples A-G
A series of block copolymers within the scope of the present
invention as well as comparative random copolymers outside the
scope of the present invention were prepared. In each of these
examples, the reactants for the aromatic polyester (a) were charged
into the reactor vessel along with the long chain ether glycol and
the preformed dimer ester polymer.
Typically, the compositions of these examples were prepared by
adding to the reactor vessel dimethyl terephthalate; a molar
excess, as compared to the terephthalate, of butanediol;
poly(tetramethylene ether)glycol (Polymeg-molecular weight 1000 and
2000); and the dimer ester polymer or, in the case of the
comparative examples, the reactants therefore, along with Goodite
3125 stabilizer and a titanate ester catalyst. The reaction mixture
was heated from 165.degree. C. to 240.degree. C. for a sufficient
amount of time until approximately the theoretical amount of
methanol was generated. A vacuum was then applied to build a high
molecular weight, high viscosity block copolymer. Reaction times
were generally about 3 hours at 250.degree. C. under 0.5 mmHg
vacuum.
The compositions of the block copolymers and the comparative random
copolymers as well as the physical characteristics thereof were as
presented in Table I. In each of the comparative examples, the
amount by which the dimer ester reactants were added to the
reaction mix was equivalent to that amount necessary to prepare the
amount of preformed dimer ester polymer.
These examples and comparative examples demonstrate various dimer
ester polymers; various weight ratios of the aromatic polyester
block(s), the long chain ether glycol blocks(s) and the dimer ester
polymer blocks(s), as well as various long chain ether glycols.
These examples and comparative examples as well as the results
obtained are as set forth in Table I.
TABLE I
__________________________________________________________________________
PBT Polymeg Dimer Ester Block Copolymer Example % MW % Diol
Viscosity.sup.a % Tm.sup.b Tc.sup.c IV.sup.d @ 25.degree. C..sup.e
@ 70.degree. C..sup.e
__________________________________________________________________________
1 63.1 1000 31.7 ethylene glycol 81,600 5.2 194 148 1.02 18 48 A "
" " " -- " 194 143 1.00 23 54 2 " 2000 " butanediol 168,000 " 206
147 1.01 24 55 B " " " " -- " 204 143 28 59 C 65 2000 35 -- -- --
206 1.10 40 73 3 63.1 1000 31.7 hexanediol 155,000 5.2 191 147 1.05
24 57 D " " " " -- " 192 137 1.08 33 61 4 60.0 2000 30.1 " 155,000
9.9 195 144 0.94 E 60.0 " 30.1 " -- " 178 128 0.85 5 63.1 2000 31.7
" 155,000 5.2 201 159 1.07 23 57 6 79.8 " 15 " 84,800 " 206 156
0.98 7 54.8 " 40 " 69,200 " 198 141 1.07 8 63.1 " 31.7 neopentyl
glycol 36,800 " 202 155 1.10 23 47 F " " " " -- " 201 150 1.04 32
54 9 " " " 2-octyl undecane 150,400 " 201 146 0.94 diol 10 " 1000 "
2-octyl undecane 40,000 " 192 140 0.94 27 60 diol G " 1000 "
2-octyl undecane -- " 188 140 1.03 28 61 diol 11 57.1 2000 28.6
2-octyl undecane 150,000 14.3 185 1.09 diol 12 " " " 2-octyl
undecane 19,000 " 185 0.94 diol 13 " " " hexanediol 46,400 " 185
122 1.11 23 53 H " " " " -- " 185 120 1.15 26 57 14 63.1 " 31.7 "
51,200 5.2 201 151 1.17 14 39
__________________________________________________________________________
.sup.a Viscosity is expressed as Brookfield Viscosity in centipoise
as determined at 60.degree. C. with a No. 6 spindle. .sup.b Melting
temperature of resultant copolymer. .sup.c Crystallization
temperature of resultant copolymer. .sup.d Intrinsic Viscosity of
resultant copolymer expressed in dl/g as determined in a 60:40
phenol/tetrachloroethane mixture. .sup.e Compression set at
25.degree. C. as determined by ASTM 395B.
From Table I it is clear that the dimer ester block modified block
copolyetheresters of the present invention have generally improved
melt temperatures, crystallization temperatures and/or compression
sets as compared to unmodified and dimer modified random
copolyetheresters. These findings are fairly consistent at various
dimer ester and poly(tetramethylene ether)glycol (Polymeg) loadings
and with the use of various molecular weight polymegs and various
dimer esters. From examples 10 and G, it is apparent that with the
higher molecular weight diols, the difference in compression set is
less clear, as compared to, for example, examples 1 and A and 3 and
D, however, the benefits of the present invention are still
present.
Comparison of examples 2, B and C demonstrates the benefit of the
present invention most clearly. Specifically, the unmodified
copolyetherester (c) has excellent melt and crystallization
temperatures, but very poor compression set. Dimer modified random
copolyester B has good compression set but loses melt temperature
and crystallization temperature. However, unexpectedly, the block
copolymers of the present invention, Example 2, retains the high
melt and crystallization temperatures of the unmodified
copolyetherester yet has even better compression set than the dimer
modified copolyetherester. Additionally, the compositions of the
present invention had excellent shore D hardness, Bayshore
resilience and other elastomeric stress-strain characteristics.
Thus the compositions of the present invention have greater utility
and better properties than the prior art compositions.
EXAMPLE 14
An additional block copolymer of the present invention was prepared
by way of a two pot reaction. Initially, a low molecular weight
dimer ester polymer was prepared from hexanediol and dimer acid.
Concurrently in a second reactor, a low molecular weight (IV about
0.65) poly(butylene terephthalate) was prepared from
dimethylterephthalate and 1,4-butanediol with a titanate ester
catalyst. In each system the reactants were heated from 160.degree.
C. to about 240.degree. C. until the theoretical amount of
volatiles and/or water was removed. Vacuum was then applied to the
system for about 1.5 hours at 1 mmHg. At this point the vacuums
were broken and polymeg 2000 and the dimer ester polymer added to
the poly(butylene terephthalate) reactor along with Goodite 3125
stabilizer and additional titanate ester catalyst. Vacuum was
reapplied and the reaction held at 250.degree. C. and 0.5 mmHg for
about 3 hours. The resultant polymer had the properties set forth
in Example 14, Table 1. Comparison of Example 14 with Example 5
demonstrates the even greater compression set of the triblock
copolymer wherein the aromatic polyester is preformed prior to
polymerization of the block copolyester ether.
Obviously, other modifications will suggest themselves to those
skilled in the art in light of the above, detailed description. All
such modifications are within the full intended scope of the
present invention as defined by the appended claims.
* * * * *